Detector System

ABSTRACT

The system includes an active unit, such as a detector unit, which has a processor, a network port for connection to a central control unit, and an optical data input port. The processor is arranged to enable the optical data input port on receipt of an enable signal received by the active unit from the central control unit via a network.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.13/877,045, filed on Aug. 2, 2013, which is a § 371 National PhaseApplication of International Application No. PCT/GB2011/001445, filed onOct. 4, 2011, which claims priority to United Kingdom Application No.1016681.7, filed on Oct. 4, 2010.

All of the afore-mentioned applications are incorporated herein by thisreference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to detector units of detector systems,such as fire alarm systems, to the detector system as a whole, to aremote communication device, and to associated methods of operation.

Modern fire alarm systems include a number of fire detector units andancillary units which are connected to a common wired network togetherwith a central control unit to which the network and all of thedetectors and other ancillaries are connected. The central control unitin this specification is control and indicating equipment whichinstructs each fire detector unit and ancillary unit to perform varioustasks during commissioning of the system, maintenance or diagnostictesting, and which controls the alarm system and the various units onthe system. The fire detector and ancillary units are normally connectedto the central control unit on one or more circuits or loops, with eachend of the circuit terminating at the central control unit. Thus, if thecircuit is broken at any one point, power and control signals can stillreach every detector or ancillary unit because each end of the circuitis connected to the central control unit. Alternatively, the detectorand ancillary units can be connected to the central control unitradially, or in other ways, such as a spur.

There are a number of operations which the central control unitinstructs the detector units and ancillary units to perform. These caninclude putting units in different operating modes, activation of selftest routines, programming the unit with a unique device identificationand ancillary functions such as switch control.

It may be necessary for manual interaction with the units so as tofacilitate or confirm operation of each unit's functions. For example,automated addressing algorithms from the central control unit can beused to uniquely identify and communicate with units on a wired network,but they may not be able to identify the physical location of each unit.During the commissioning process, in which the system is initially setup for correct functioning, an operator is required to be in a positionnear to the individual units. During the commissioning process, as wellas testing the operation of the individual units, the nearby operatorwill need to identify the location of each unit. This normally requiresa second operator at the central control unit who will send commandsthrough the wired network to the unit near to the nearby operator suchthat a visible LED on the casing of the unit is caused to flash. Thenearby operator must then communicate the location of the unit back tothe operator at the central control unit perhaps by telephone or radio.The operator at the central control unit can then enter or confirm apre-programmed location of the unit, for example “Conference Room 2” andsend this through the wired network to the unit concerned where thelocation is stored in memory.

An alternative method exists in which a single operator carries aportable tool which he carries around the building so that, when hereaches a unit, he removes it from its mounting and connects it to theportable tool and uses the tool to write the location of the unit intothe unit's memory. He then replaces the unit into its housing. Thissystem has a number of problems in that units tend to be located inplaces which are difficult to access, such as high up on ceilings and inroof voids which require the use of specialist removal, climbing orlifting equipment to obtain access. This adds to the resources which arerequired to commission a system, and are time consuming, therebyincurring high commissioning, maintenance and diagnostic costs.

It has been proposed that remote devices are used to communicate withthe units based on radio frequency (RF) signals, but there are a numberof problems associated with this. Firstly, RF signals propagate overlong distances and lack directionality. Thus, any signal which isemitted from the remote device is likely to be received by several unitswithin the building. Also, many other devices operate using RF signals,meaning that there is a possibility of interference between the systems.It would be very undesirable for a unit to receive a signal from anothersystem which causes it to enter a test mode whereby, if it were todetect the presence of a fire, it would not set off an alarm signal. Itwould also be undesirable if the remote device were to succeed inprogramming more than one unit at a time, when it is only intended to beused to program one of them. RF systems also tend to be very expensive.

Reference is made to ‘detector systems’. In the specification, this termincludes systems, such as fire alarm systems, emergency alarm systems,intruder alarm systems and the like. The systems include a number ofactive units which are networked together, often on a circuit. The term‘active units’ includes detector units for detecting whatever it is thatthe system is designed to detect, as well as ancillary units havingdifferent functions, such as sounders for generating an audible alarm,flashing beacons which provide a visual alarm, isolator units which canbe used to isolate parts of a detector circuit, alarm activation buttonsor switches, and the like. Where it is a fire detector system, thedetector unit might be a smoke detector, heat detector, flame detectoror the like. Where the detector system is an emergency detector system,it will include suitable detectors for detecting an emergency, such asthe presence of toxic gases, the presence of radioactivity, or someother suitable indicator of an emergency. In the case of an intrusiondetector system, the detector units might be movement detectors, heatdetectors, pressure sensors, and the like.

SUMMARY OF THE INVENTION

The present invention aims to address some of these problems.

According to a first aspect of the present invention, an active unit ofa networked detector system comprises; a processor; a network port forconnection to a central control unit; an optical data input portarranged to receive optical data, wherein the processor is arranged toenable the optical data input port on receipt of an enable signalreceived by the active unit from the central control unit via thenetwork.

By enabling the optical data input port only when it is required, forexample while the system is being commissioned, maintained, ordiagnosed, the possibility of interference from other optical sources isless likely to have an effect on the active unit. Additionally, the useof optical data reduces the likelihood of large numbers of active unitsbeing addressed by a remote communication tool. Optical signals are muchmore directional than RF signals.

Preferably, the active unit further comprises an optical data outputport arranged to transmit optical data. This permits the active unit totransmit data, for example, to a remote communication tool.Alternatively, the optical data output port might be an LED whichpermits the operator of a remote communication tool to be notified thatthe optical data has been safely received by the active unit and,perhaps, acted upon.

Advantageously, the active unit further comprises a multiplexer whichselects data from the optical data input port or the network port. Itwill be appreciated that the active unit can be addressed both by thecentral control unit via the network port, and optically via the opticaldata input port. In some embodiments, the active unit may be able toreceive and act upon data received both via the network port and by theoptical data input port, but other systems will only be able to receivedata from either the optical data input port or the network port at anyparticular moment. The multiplexer may be arranged to assign a higherpriority to data received from the optical data input port than from thenetwork port.

The multiplexer is preferably ranged to select data from the opticaldata input port when data is received from the optical data input portand data from the network port when it is not.

It is also advantageous for the active unit to include a watchdog unitarranged to monitor received optical data, and if more than apredetermined amount of data is received which is not recognised as datarelating to the active unit, the optical data output port is disabled.

The watchdog unit is intended to reduce the likelihood of other opticalsources interfering with the detector unit.

It is also preferred that the active unit include an optical signaldetector which detects the presence of optical signals received by theoptical data input port further, the active unit may include a logicunit which is arranged to control the multiplexer, the logic unitincluding a first input for receiving the optical port enable signal anda second input for receiving a signal indicating if an optical signal isbeing received, and wherein the logic unit is arranged to control themultiplexer to select data from the optical port when both the opticalport is enabled and an optical signal is received.

It is preferred that the optical data output port is an infra-red (IF)port, and the optical data is IR data.

According to a second aspect of the invention, a detector systemincludes the active unit according to the first aspect of the inventionand a remote communication device including an optical data output portarranged to transmit optical data. Preferably, that remote communicationdevice further includes an optical data input port arranged to receiveoptical data.

The remote communication device can be used to communicate with theactive unit.

In one embodiment, the remote communication device further includes aprocessor unit arranged to generate data for transmission from theoptical data output port of the remote communication device. Thispermits it to communicate with the active unit. The remote communicationdevice further comprises a display. If the active unit emits a reply,this can be viewed on the display.

According to a third aspect of the present invention, a detector systemcomprises an active unit according to the first aspect of the inventionand a central control unit having a network port for communication tothe active unit via the detector network, the central control unithaving an optical data port enabler arranged to generate an enablementsignal which is communicated to the active unit via the detectornetwork. This enables an operator to generate an enablement signal toactivate the optical data ports of some or all of the active units whilethe system is being commissioned, maintained or diagnosed.

The central control unit further includes a disabler which is able togenerate a disablement signal for communication to the active unit(s)via the detector network. This allows the operator to turn the opticaldata ports off when they are not required.

According to a fourth aspect of the present invention, a remotecommunication device arranged to communicate with an active unit of anetworked detector system which has an optical data input port includesan optical data output port arranged to transmit optical data; and anoptical data input port arranged to receive optical data. The input andoutput port may be a single component.

The remote communication device preferably also includes a processorunit arranged to generate data for transmission from the optical dataoutput port of the remote communication device. The remote communicationdevice might also include a display.

According to a fifth aspect of the invention, a method of communicatingwith an active unit of a detector network, wherein the active unitincludes an optical data input port, comprises the steps of: 1.generating an optical data input port enablement signal at a centralcontrol unit which is arranged on the detector network; 2. receiving theoptical data input port enablement signal in the active unit; and 3.enabling the optical data input port of the active unit.

Preferably, the method further comprises receiving an optical data inputsignal via the optical data input port. Preferably, the method alsoincludes transmitting optical data from the optical data output port ofthe active unit.

According to a sixth aspect of the present application, a method ofselecting one active unit to communicate with from a plurality of activeunits on a networked detector system, each active unit including anoptical data input port for receiving optical data, the methodcomprising the steps of: 1. transmitting an optical initiation signedtowards the active unit to be selected; 2. receiving optical handshakesignals from the plurality of active units; and 3. selecting the opticalsignal from the active unit to be selected.

In this way, if the optical initiation signal is received by multipleactive units, each of those active units will send an optical handshakesignal which allows a particular active unit to be selected based on theoptical handshake signal from the active unit.

The optical initiation data may be transmitted from a remotecommunication device. Preferably, the optical handshake signals from theplurality of active units differ from each other, for example byincluding the address information identifying the active unit that hassent it.

Preferably the optical data input port of each active unit is an IRport.

It is preferred that the remote communication device includes a selectorby which the active unit can be selected, and that the selector can be akey, a button or an icon which is operated to select the active unit.Alternatively, or in addition, the selector includes a display which isarranged to display the handshake signals from the active units, fromwhich the active unit may be selected.

In one embodiment, the plurality of active units each include a visibleLED which transmits the optical handshake signal for that detector.

According to a seventh aspect of the present invention, an active unitcomprises an optical data input port for receiving optical signals; aprocessor arranged to identify an initiation signal from the receivedoptical signal; and an optical signal output port arranged to emit anoptical handshake signal when an initiation signal is received.

The optical signal output port may be an LED, and the active unit mayinclude a memory which stores the handshake signal. The handshake signalmay be a unique identifier of the active unit, perhaps including thenetwork address of the active unit.

According to an eighth aspect of the present invention, a remotecommunication device arranged to communicate with a selected one of aplurality of active units comprises a processor arranged to generate aninitiation signal; an optical data output port arranged to emit theinitiation signal; an optical data input port arranged to receive aplurality of handshake signals from the plurality of active units; aselector operable to select one of the active units from which ahandshake signal is received.

The selector may be a key, button or icon which is operated to selectthe active unit. The device may also include a display which is arrangedto display the handshake signals from the active units from which theactive unit may be selected. Preferably, the optical data output portsand the optical data input port are IR ports.

According to the ninth aspect of the invention, a detector systemcomprises an active unit having an optical data input port for receivingoptical signals; a processor; an optical signal output port; and aremote communication device arranged to communicate with a selected oneof a plurality of active units including a processor arranged togenerate an initiation signal and an optical data output port arrangedto emit the initiation signal; wherein the processor of the active unitis arranged to identify the initiation signal from the received opticalsignal and the optical signal output port is arranged to emit an opticalhandshake signal when the initiation data is received.

According to a tenth aspect of the present invention an active unit of anetwork safety system comprises a protocol decoder; a network port forconnection to a central control unit; an optical data input portarranged to receive optical data; a multiplexer which receives data bothfrom the network port and from the optical data input port and passesthe data to the protocol decoder, wherein the protocol decoder isarranged to apply the same protocol decoding process to data from boththe network port and the optical data input port.

By using a common protocol between the optical data from the opticaldata input port and the data from the network port, the two sets ofsignals can be handled in exactly the same way requiring a singleprotocol decoder. It is surprising that this is possible, because itwould be expected that the data transmission rate through an opticaldata system would be much less than a wired system because of thepotential level of interference, reflections and the like whencommunicating remotely using an optical signal. Normally, opticalsignals are transmitted at a very low data transfer rate which would beincompatible with the data transmitted over a wired data network, and sotwo different protocol decoders would have been expected, but by usingthe same protocol, a single protocol decoder can be used. This makes thesystem significantly cheaper and makes operation of the detector unitsimpler.

Preferably, the optical data input port is an IR port.

Additionally, the active unit may include a processor which operates onthe decoded data from the protocol decoder, and the protocol decoder maybe part of the processor.

Preferably, the multiplexer assigns a higher priority to data receivedfrom the optical data input port than from the network port. This may beimportant where the active unit can only handle data from one of theports at a time.

The active unit may also comprise an optical data output port arrangedto transmit optical data, and a de-multiplexer which is arranged toreceive data from the protocol decoder and to pass it to the networkport or to the optical data output port, as appropriate. Thus, theactive unit can communicate both with the central control unit and anyremote communication device.

According to an eleventh aspect of the invention, a detector systemcomprises an active unit according to any one of the preceding claims; aremote communication device including an optical data output portarranged to transmit optical data, and a protocol encoder whichgenerates optical data configured to use the same protocol as datareceived by the active unit via the network port.

The optical data output port may be an IR port, and the remotecommunication device may include an optical data input port arranged toreceive optical data.

According to a twelfth output of the invention, a method of receivingdata from a network and from an optical data input port by an activeunit having a network data port, a protocol decoder and a multiplexer,comprises receiving data both from the network port and from the opticaldata input port; passing the data to the protocol decoder; decoding thedata in the protocol decoder by applying the same protocol decodingprocess to data from both the network port and the optical data inputport.

Preferably the method further includes the steps of generating opticaldata configured to use the same protocol as data received by the activeunit via the network port in a protocol encoder of a remotecommunication device; and transmitting the optical data from an opticaldata output port in the remote communication device.

The above and other features of the invention including various noveldetails of construction and combinations of parts, and other advantages,will now be more particularly described with reference to theaccompanying drawings and pointed out in the claims. It will beunderstood that the particular method and device embodying the inventionare shown by way of illustration and not as a limitation of theinvention. The principles and features of this invention may be employedin various and numerous embodiments without departing from the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, reference characters refer to the sameparts throughout the different views. The drawings are not necessarilyto scale; emphasis has instead been placed upon illustrating theprinciples of the invention. Of the drawings:

FIG. 1 is a block diagram showing a detector system according to thepresent invention;

FIG. 2 is a block diagram showing a detector unit in communication witha remote communication device;

FIG. 3 is a block diagram showing a central control unit;

FIG. 4 is a block diagram showing one way of connecting a computer tothe system;

FIG. 5 is a block diagram showing another way of connecting a computerto the system; and

FIG. 6 is a flow diagram, split into parts 6.1 to 6.6, showing theprocess of commissioning a system or a part of a system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which illustrativeembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Further, the singular formsand the articles “a”, “an” and “the” are intended to include the pluralforms as well, unless expressly stated otherwise. It will be furtherunderstood that the terms: includes, comprises, including and/orcomprising, when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof. Further, it will be understood that when anelement, including component or subsystem, is referred to and/or shownas being connected or coupled to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent.

It will be understood that although terms such as “first” and “second”are used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. Thus, an element discussed below could betermed a second element, and similarly, a second element may be termed afirst element without departing from the teachings of the presentinvention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Referring first to FIG. 1, a detector system 1 is shown including acentral control unit 2, a wired network 3 which connects the centralcontrol unit 2 to a plurality of detector units 4. The wired network 3is normally in the form of a circuit or loop, with each end of thenetwork connected together back at the central control unit 2. Multipledetector units 4 can be carried on the wire network 3, and in FIG. 1,these are labelled unit i1, i2, i3, i4, . . . , i−m. Alternatively,these units can be connected in parallel, or as a spur. The wire network3 supplies power to each of the detector units 4, as well as acting as acommunication network.

The system also includes a remote communication device 5 which cancommunicate directly with the detector units 4 by use of an IRcommunication link 6. In this case, the remote communication device 5 isintended to communicate with unit i3, but there is unintendedcommunication with units i2 and i4 as well, because they are in closeproximity. Units which are not in close proximity will not be affected.

Referring now to FIG. 2, a detector unit 4 and a remote communicationdevice 5 are shown schematically in block form with an IR communicationlink 6 between them.

Referring first to the detector unit 4, it will be seen that it isconnected to the wire network 3. The point at which the wire network 3enters the detector unit forms a network data port 7. Of course, thatnetwork brings not only data communication, but also power to drive thedetector unit 4. Data received from the central control unit 2 via thenetwork data port 7 is passed to a wired network input filter 8, andoutgoing data being passed to the wired network via the network dataport 7 comes from a wired network output filter 9. The filters 8 and 9are connected to a multiplexer/demultiplexer 10. Themultiplexer/demultiplexer 10 also receives data from an IR receiver 11and directs data to an IR transmitter 12.

Data received by the multiplexer/demultiplexer 10 from the network dataport or from the IR receiver is directed to a processor unit 13 and datasent from the processor unit 13 is directed to themultiplexer/demultiplexer 10 which directs it to the network data port 7or the IR transmitter 12, as appropriate. The multiplexer/demultiplexer10 selects which of the incoming signals from the network data port 7and the IR receiver 11 it will pass to the processor 13, and which oneof the network data port 7 and IR transmitter 12 that it will sendoutgoing data to based on a chip select/enable signal received at inputC. The IR receiver and transmitter can be switched on and off based onwhether the IR receiver and transmitter are enabled. This is determinedby a signal from the processor unit 13, as well as a signal from an IRcommunications or carrier detector 14 which are passed to an AND gate.When both signals are high or ‘1’, the multiplexer/demultiplexer 10routes messages to and from the ‘IR receiver 11 and IR transmitter 12.The IR communications or carrier detector 14 monitors the IR receiver 11such that, as soon as the IR receiver 11 receives an IR signal, it sendsa high or “1” signal to the AND gate for a period of time, in this casetwo seconds. This gives the multiplexer 10 sufficient time to receiveand forward the data received by the IR receiver 11 to the processorunit 13. This also gives the processor sufficient time to send any replysignal to the IR transmitter 12 before the multiplexer returns tocommunicating with the network port 7.

The detector unit 4 also includes a sensor, monitor, indicator andswitch array 15 and a visual indicator 16, such as a visible LED. Theremote communication device is also shown and includes an IR receiver 17and an IR transmitter 18. These are connected to a device processor unit19, which is also connected to a display 20 and a keypad 21. Anyappropriate user interface is possible here. The display could includeactive areas, like on a PDA, which can be touched to make selections orto enter data. The remote communication device 5 is able to transmitdata from the IR transmitter 18 to the IR receiver 11 of the detectorunit 4, and the IR transmitter 12 of the detector unit 4 is able totransmit data to the IR receiver 17 of the remote communication device5.

FIG. 3 shows a central control unit 2 schematically. It is connected tothe wired network 3, and includes a panel processor 32 which isconnected to a protocol encoder 33 and a protocol decoder 34. Each ofthese is connected to a loop driver 35 which is powered by a powersupply 36, and connected to the wired network 3. When the processorsends data or a command to a detector unit 4, the data is sent to theprotocol encoder 33 which encodes it into a format ready fortransmission through the wired network 3 via the loop driver 35. When adata signal is received by the central control unit 2, it is received bythe loop driver 35 which directs it to the protocol decoder 34 whichdecodes the data into a form in which the processor 32 can understand.The signal or data passing through the wired network 3 is superimposedon the voltage across the wire network established by the power supply36.

During normal operation, the IR transmitters and receivers of thedetector unit 4 are disabled. Most of the time, they serve no purpose.The detector unit 4 simply needs to communicate with the central controlunit 2. Not only would the IR receiver and transmitter 11, 12 drain aconsiderable amount of power over a long period of time, but they wouldalso pose a security risk if they were enabled since it might bepossible for someone to gain access to the processor of the detectorunit 4, or for background IR signals from other devices to causeinterference with the detector unit 4. However, from time to time, it isnecessary for the detector unit 4 to be accessed directly, whenconnecting via the IR link is important. For security reasons, before aperson connects using the remote communication device 5, the person mustfirst enable the IR receiver 11 and transmitter 12 from the centralcontrol unit 2. The central control unit 2 offers security on thisfeature such that only authorised personnel are able to enable the IRreceiver and transmitter 11, 12. The central control unit 2 directs anenablement signal through the wire network 3 via the protocol encoder 33and loop driver 35 to the detector unit 4. This enable signal mightapply to a single detector unit, or to all detector units within thesystem or circuit. The IR enablement signal is received by the detectorunit 4 via the network 3 such that the signal enters via the networkdata port 7 and passes through the wired network input filter 8 and themultiplexer/demultiplexer 10 so as to be received by the processor unit13. On receiving the IR enablement signal, the processor unit 13 outputsa ‘1’ signal on the commissioning mode enable line to the AND gate, andcauses the IR receiver 11 and IR transmitter 12 to be powered. A personmay then operate the remote communication device 5 directing signalsfrom it from its own IR transmitter towards the detector unit 4. Thedata signal will be received by the IR receiver 11, and detection of anIR signal is communicated by the IR communication or carrier detector 14to the other input of the AND gate, where upon a positive chip selectsignal C is directed to the multiplexer/demultiplexer 10 for a period of2 seconds. This chip select signal causes the multiplexer/demultiplexer10 to transfer data from the IR receiver 11 to the processor unit 13 inpreference to any data received via the network data port 7 from thenetwork 3. It also directs any data from the processor unit 13 outthrough the IR transmitter 12 rather than through the network port 7.Thus, the chip select signal controls the routing of output signals, andthe source of input signals.

After two seconds without any IR signals being received, the IRcommunication or carrier detector changes its output to ‘0’, whichcauses the chip select signal to drop to ‘0’ and the multiplexer toswitch so as to communicate with the wired network.

Once the person has finished communicating with the detector unit 4, hewill return to the central control unit 2 and switch off the IR receiver11 and 12 by causing the processor 32 of the central control unit 2 tosend a disablement signal through the protocol encoder 33 and the loopdriver 35 to the network 3 where it is received by the detector unit 4.The processor unit 13 within the detector unit 4 switches thecommissioning mode enable output to zero, thereby switching off the chipselect signal C to the multiplexer/demultiplexer 10. The power to the IRreceiver and transmitter 11, 12 is also switched off.

It is useful, at this point, to say something about the remotecommunication device and its use in conjunction with the detector unit.For example, during the commissioning process, in which the system isinitially set up for correct functioning, an operator is required to bein a position near to the individual detector units during thecommissioning process. During that process, as well as testing theoperation of the individual units, the nearby operator will need toidentify the location of each unit. Rather than remove the detectorunits and attach them to a portable tool to carry out operations such asentering the location of the detector into the detectors memory, thepresent invention allows this to be done remotely without removing thedetector unit from its mounting point. The keypad 21 of the remotecommunication device 5 can be used to enter data, such as the locationof the detector unit, or any other appropriate information which canthen be sent to the detector unit 4 to be entered into memory. Thedisplay 20 of the remote communication device 5 might be used to displaydata which is transmitted from the detector unit 4 to the remotecommunication device 5. The processor unit 19 receives IR data which hasbeen received by the receiver 17, and transmits data to the IRtransmitter 18 so as to be directed to the detector unit 4. Theprocessor unit 19 is able to decode the received signals into a formthat it is able to understand, and encodes outgoing data into a formwhich can be transmitted via the IR transmitter 18. Likewise, theprocessor unit 13 is able to decode incoming signals and encode outgoingsignals for transmission to the remote communication device 5.Significantly, communications between the detector unit 4 and thecentral control unit 2 are encoded in the same way, despite the factthat communications between the detector unit 4 and the central controlunit 2 are transmitted via a wire network 3 rather than the IR linkbetween the detector unit 4 and the remote communication device 5. Thisis a very surprising arrangement since it is expected that you wouldneed to have different data transmission protocols depending on themeans of communication. One would expect the IR link to have a very slowtransmission rate, and to have completely different characteristics tothe communication over the wire network 3. However, it has been foundthat the same protocol can be used for both. This offers severaladvantages in that the processor unit 13 in the detector unit 4 onlyneeds to have a single protocol encoder/decoder, and does not need tohave a separate one for each means of communication. This reduces thecost of the processor unit 13 and simplifies the detector unit 4. Sinceonly a single decoder is required within the processor 13, themultiplexer/demultiplexer is important because the processor 13 can onlyreceive data from one of the communication sources at a time, and whenthe IR communication link is active, the processor unit 13 will be“deaf” to the wired network 3. However, when the IR receiver is notreceiving any data, this is detected, and the multiplexer/demultiplexer10 is switched back to communicating with the wired network 3. The IRcommunication or carrier detector 14 which detects whether there are IRsignals being received could operate in a number of different ways, forexample by detecting wireless data packets or a preamble, or the headerof a particular type of wireless packet. In effect, themultiplexer/demultiplexer is a switch.

While the IR receiver 11 is active, it could pick up IR signals fromother sources which are nearby, such as powerful light sources, strobes,or remote control devices for televisions. These could cause thedetector unit to erroneously believe that it is being communicated with,hence preventing communication from passing to and from the detectorunit via the wired network 3. This is why the IR mode of operation isonly enabled when an operator with the appropriate security access levelenables the IR mode from the central control unit 2. However, while theIR mode is enabled, another IR source could interfere with the detectorunit by the continued presence of IR activity beyond what is expected.The present invention employs a watchdog time out system based on atimer and triggered by a continued presence of IR activity beyond whatis expected for a period. The central control unit can be arranged tosend an additional enablement command signal to the detector unit every,say, 10 or 20 seconds. Since the processor unit is ‘deaf’ to the centralcontrol unit while it is receiving IR data, if this additionalenablement command isn't received by the unit on, say, four consecutiveoccasions, this will indicate that the IR receiver is being interferedwith by a background source of IR activity, and the IR mode can beswitched off. This can be carried out by the processor unit, which wouldswitch the commissioning mode enable line to ‘0’.

Another possibility is for the detector unit to have a test function totest for unwanted sources of IR activity, so setting an input forenabling the IR communication parts. The IR circuit will be activated,but the multiplexer will be set to keep the detector in Loop mode only,and the output that drove the C input (of the multiplexer/demultiplexer)is instead routed to an input on the processor which can be interrogatedby the panel, thus determining if there is unwanted IR activity beforethe IR link is actually activated. Conveniently, an ‘unwanted IRactivity’ report for all units on the loop can quickly be generated andindicated at the panel to the user at the time of IR enablement. Thecentral control unit 2 will interrogate the IR receiver 11 (using afurther command), confirming that there is no unwanted IR activitybefore sending the command to enable the IR communication mode.

The operation of the invention will now be described. Let us assume thatthe system has just been installed and is in the process of beingcommissioned. The commissioning process involves checking each of thedetectors, and entering into the memory of each detector the location ofthat detector. The operator begins at the central control unit 2 byinstructing the central control unit to place the detectors in IR modesuch that the IR receivers and transmitters 11, 12 are enabled. Thiswill require the operator to identify themselves as having sufficientsecurity clearance to carry out that action.

The operator will then approach a detector unit 4 with the remotecommunication device 5 such that the remote communication device 5 iscaused to emit an initiation signal from the IR transmitter 18. Thedetector unit 4 receives that signal, and recognises it as a systemsignal, where upon the IR communication or carrier detector 14 passes asignal to the AND gate so as to direct the multiplexer/demultiplexer 10to pass the initiation signal to the processor 13. This establishescommunication between the remote communication device 5 and the detectorunit 4. The processor unit 13 sends a handshake signal which is directedby the multiplexer/demultiplexer 10 to the IR transmitter 12 whichtransmits it to the IR receiver 17 of the remote communication device 5.This establishes communication between the two devices. The remotecommunication device can then call for the data which appears within thememory of the detector unit corresponding to the location of thedetector unit. This information is sent to the remote communicationdevice, where it is displayed on the display 20. If the operator wishesto change the location of the unit recorded in its memory, he can editit using the keypad 21 and return it to the detector unit 4 via the IRlink so as to update the field within the memory of the detector unit 4.

The operator could also carry out various other operations, such asinitiating test modes, if he wishes. When the operator is finished, heends communication with the detector unit and returns to the centralcontrol unit where he causes an IR mode disablement signal to be sent tothe detector, which then ends the IR mode. This command could also besent from the remote tool itself.

It will be appreciated that, in certain circumstances, a number ofdetector units may be positioned close together, and that, when theoperator sends the initiation signal to the detector unit 4 that heintends to communicate with, several detector units may receive thatinitiation signal and return handshakes. One way in which the operatoris able to discriminate between the detector units is where thehandshake signals from each of the detector units are unique, perhapsincluding the address or the unique serial number of the detector unit.These could then be displayed on the display 20 of the remotecommunication device 5, and the operator can select the one which hewishes to communicate with.

Alternatively, instead of the handshake signal being one which is sentfrom the IR transmitter 12 of the detector unit, it could be directed tothe visual indicator 16, such as a flashing LED. If the LEDs of eachdevice are arranged such that they will flash at different times, theoperator can select the detector that he is interested in communicatingwith simply by making a selection on the remote communication device 5when the detector unit he wishes to communicate with flashes. This mayrequire a software algorithm to be in place such that, when the detectorunits 4 send their handshake signals, they are sent at different times.Alternatively, the time at which the handshake signal is sent may bepre-programmed.

There is also a potential for applying the existing collisionarbitration algorithm, based on a GLOBAL command. If one detector candetermine if another is in the process of transmitting a signal to theremote device, that unit can hold off sending its own message until itcan determine the first has finished sending its message. To accomplishthis, the remote tool will have to send out an IR signal as soon as itreceives one, so it acts like a mirror such that each detector within IRlink range will see the activity from the other detectors within range.This assumes the detectors have already been programmed with unique IDaddresses.

Alternatively, or if the units in range are programmed with the same(default) ID address: an auto addressing function can be used, theremote tool can attempt to communicate with individual detectors quicklyusing selected serial number values. Any clashed replies will beidentified as a collision and the next level of serial addressing willbe invoked, until all detectors are individually identified. Thistechnique does not require the remote tool to act like a mirror. In thispatent specification the embodiments described have two-way IRcommunication between the detector unit 4 and the remote communicationdevice 5. In other embodiments, the IR link may be one way such that thedetector unit only includes an IR receiver 11, and no IR transmitter 12.The visual indicator 16 becomes important since the operator will needto know whether the detector unit has received or implemented thecommands sent to the detector unit from the remote communication device5. This means that the remote communication device 5 only requires an IRtransmitter 18, and no IR receiver 17. Clearly, the functionality of thesystem is reduced if the IR link between them is only one way.

A further embodiment in which the whole or a part of a detector systemis commissioned will now be described with reference to FIGS. 4, 5 and6. As in the above embodiments, a central control unit 2 is connectedvia network to a plurality of detector units. The commissioning processrequires the use of a computer 41 executing detector systemconfiguration software by which the detector system can be defined. Forexample, the computer system can allow a user to define the connectionsfrom the central control unit 2 to the various detector units, sounders,call points and the like within the system. Each component within thesystem can be allocated a unique address on the system, the location ofeach detectors can be identified, and the appropriate properties of eachdetector unit can be defined, for example sensitivity level and thelike. Once the system has been defined by the software running on thecomputer 41 as configuration data, that configuration data can bedownloaded onto the central control unit 2 and the remote communicationdevice 5. This can be downloaded in a number of different ways. In FIG.4, the computer 41 is shown connected both to the central control unit(2) and to the remote communication device 5 so as to download theconfiguration data directly. The arrangement shown in FIG. 5, however,shows the configuration data being downloaded from the computer 41 tothe central control unit 2, and then being sent from the central controlunit 2 to the remote communication device 5.

The commissioning process of this embodiment will now be described indetail with reference to the flow diagram of FIG. 6. The length of theflow diagram is such that the process is spread over six pages. In theflow diagram, the process is divided into four columns representing theaction taken by an engineer; by the central control unit 2; by theremote communication device 5; and by the detector unit 4.

In step 61, the installing engineer configures the whole or a part ofthe detector system on a computer using detector system configurationsoftware executing on the computer 41. Once complete, he downloads theconfiguration in the form of configuration data to the central controlunit 2 in step 62, and to the remote communication device 5 in step 63,these steps corresponding to the arrangement shown in FIG. 4. If thearrangement of FIG. 5 is used, the configuration data is downloaded tothe remote communication devices by the central control unit 2.

The engineer will then prepare to test the commissioning of eachdetector unit 4 by placing the system in a test mode in step 67 and 68by switching the IR mode on at the central control unit 2. The centralcontrol unit 2 will send an “IR mode ON” command to the required sectionor loop of the detector system every five seconds, or where the wholesystem is being commissioned for the first time, to the whole system.This takes place in step 69. The “IR mode ON” command is sent to therelevant detector units 4, and in step 70, each of those detector units4 receives the signal and enters its IR mode.

The engineer will take the remote communication device 5 and place it incommissioning mode in step 51. In step 52, the remote communicationdevice will check all devices within the configuration data of thedetector system to identify those which have not been commissioned. Ifit finds devices which require configuration (step 53), it will displaya list of those devices on its screen in step 54. The engineer can thenmove the remote communication device 5 to those detectors which have notyet been commissioned (step 55).

When the engineer reaches one of the devices from the list on the remotecommunication device 5, he will select that device from the list on theremote communication device 5 in step 71. This causes the remotecommunication device 5 to start communicating with the detector unit 4.The detector unit 4, which has not been commissioned, contains a defaultaddress which must be changed to its final commissioned address which isdefined by the configuration created by the engineer in step 61. In step72, the remote communication device 5 sends the new address of thedetector unit 4 to the detector unit 4 via the IR transmitter. Step 73achieves a handshake in which the detector unit 4 transmits by its IRtransmitter the address that it has now been programmed with. The remotecommunication device 5 compares this, in step 74, with the correctaddress, and if correct re-addressing has failed, the device is notcommissioned in step 75, and the engineer retries to set the devicesaddress, in step 76, for a few number of times. Once the address hasbeen correctly placed in the detector unit 4, the remote communicationdevice causes the detector unit 4 to be switched on, and, in step 78,this raises its power-up flag using the new address. This power-up flagis detected by the central control unit 2 in step 80, which theninitialises the device with point and zone information. This tells thedetector where it is located both within the building or environment itis located, and within the detector system. Therefore, it includesinformation on which circuit the detector unit is located as well aswhat room the detector is located in. Other configuration informationmay be transmitted to the detector unit 4, such as the sensitivity levelthat is to be used. This configuration data is stored in the memory ofthe detector unit 4 in step 82.

From step 83, the detector device 5 is maintained in IR mode, and instep 84, the detector unit 4 is asked to supply the configuration datait has received from the central control unit 2 by the remotecommunication device 5. This is requested via the IR link, and the datais sent via the IR link and is displayed on the remote communicationdevice 5 in step 86. In step 87, this is compared with the configurationdata of that detector 4 that is already stored in the remotecommunication device 5. If it is confirmed to be correct, this isrecorded in a log in step 88, and the engineer is requested by theremote communication device 5 to test the detector unit 4. The engineerthen indicates in step 90 if he will conduct the test, and on theassumption that he will, he follows the test instructions in step 91 andin step 92, and steps 93 and 94 the results of the various tests aredisplayed or recorded. The engineer records the results in step 95, andthe central control unit processes the results in a log in the centralcontrol unit in step 96. The record of the results is made in a log inthe remote communication device in step 97. If the device fails thetest, or requires a change in the configuration, the engineer will makean entry of this kind in the log within the remote communication device5 at this point. To facilitate this, the remote communication device 5includes a QWERTY keypad. Once commissioning is complete, a message isdisplayed in step 96 to that effect and information concerning the timeand date of the commissioning process is entered into the log-in step99.

Once each detector unit 4 has been commissioned, the engineer returns tothe computer 41 and activates a reporting function within the softwarein step 101. The engineer connects the remote communication device 5 tothe computer in step 102 and loads the reporting application software103 on the computer. The engineer and the reporting application gothrough various steps to import the commissioning data files to create areport in step 108. If the configuration of a detector unit 4 needs tobe changed, as noted by the engineer during the commissioning process,he will make these changes to the configuration software on the computer41, and repeat a number of the steps that he has taken during his firsttest. He will download the updated configuration data onto the centralcontrol unit 2 and the remote communication device 5, and will return tothe detector unit 4 to do a re-test. Once this is satisfactory, thecommissioning process is complete.

The remote communication device 5 can be enhanced such that, if anychanges to the configuration are required, they can be made during thecommissioning process, while the engineer is using the device tocommunicate with the detector 4. He can use the device 5 to change theconfiguration, and this updates the configuration data on the remotecommunication device 5 as well as in the detector unit. At the end ofthe configuration process, when he returns to the computer 41, thechange in configuration of the detector unit 4 is imported into theconfiguration software running on the computer 41, and this updatedconfiguration is then downloaded onto the central control unit so thatit is updated so as to correspond exactly with the configuration data ofthe detector unit.

List of Steps in FIG. 6

-   -   51 Place remote communication device 5 in commissioning mode    -   52 Check device list for devices which have not been        commissioned    -   53 Decision box to identify if any devices have not yet been        commissioned on the system    -   54 Display list of devices    -   55 Walk to detector location    -   61 Configure configuration software on computer    -   62 Download configuration from software onto central control        unit    -   63 Download configuration of system to remote communication        device    -   64 Initialise and configure any detector units not already set        up    -   65 Store configuration into memory    -   66 Raise any faults due to missing/non-addressed detector units    -   67 Enable walk test mode for detectors which are to be        commissioned    -   68 Place central control unit into IR mode for required loop(s)    -   69 Central control unit sends “IR mode ON” command to required        loop(s) every five seconds    -   70 Device switches on IR circuitry    -   71 Select the device from the list on the remote communication        device.    -   72 Send new address to device via IR link if device has default        address    -   73 Confirm address which has been programmed into device    -   74 Decision box to identify if address has been correctly        programmed into detector unit    -   75 Make note that device is not commissioned    -   76 Engineer tries this for a few number of times    -   77 Raise the power-up flag of the detector unit over the IR link    -   78 Device resets and raises its power-up flag. The detector unit        uses the new address.    -   79 Display a message to the user informing them that the device        is being configured    -   80 Panel detects power up flag for device with programmed        address    -   81 Initialises the device with point/zone information and seals        it over loop    -   82 Store configuration into memory    -   83 Device remains in IR mode    -   84 Request the device information for this address over the IR        link    -   85 Send device information over the IR link    -   86 Display the device information, remote communication device        will confirm automatically    -   87 Decision box as to whether confirmation passes or fails    -   88 An entry is made in the log against this point to show that        it is correct    -   89 A message is displayed asking the user to test the device    -   90 Decision box for the engineer to decide whether to conduct        test    -   91 User follows test instructions    -   92 User tests the device using no-climb and gas/co heat    -   93 Central control unit detects a fire and the device being        tested. Lights fire LED on device    -   94 A message is displayed asking the user if the test passed or        failed    -   95 User indicates on the remote communication device if the test        passed or failed    -   96 Process any groups/actions and make entry into the log of the        central control unit    -   97 An entry is made in the log against this point to indicate        the status of the test    -   98 A message is displayed indicating that the commissioning of        this device is complete    -   99 An entry is made in the log indicating the time and date of        commissioning complete    -   100 The main menu is displayed    -   101 User activates reporting function    -   102 User plugs remote communication device into computer    -   103 User loads reporting application    -   104 Asks the user to identify the correct data log files to use    -   105 Selects the data files    -   106 Asks the user which type of report they require    -   107 User detects “commissioning report”    -   108 Uses a combination of the remote communication device and        the configuration data files to create the report    -   109 End

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. An active unit of a networked fire detection system, comprising: a processor; a network port for connection to a central control unit, and through which communication may be received from the central control unit; an optical data input port arranged to receive optical data from communication sources external to the active unit; an optical signal detector which detects a presence of optical signals received by the optical data input port; and a watchdog unit arranged to monitor the received optical data; wherein the processor is arranged to enable the optical data input port on receipt of an enable signal received by the active unit from the central control unit via the network through the network port; and wherein the watchdog unit is arranged such that, if more than a predetermined amount of optical data is received which is not recognized as data relating to the active unit, the optical data input port is disabled.
 2. The active unit according to claim 1 further comprising an optical data output port arranged to transmit optical data.
 3. The active unit according to claim 1, further comprising a multiplexer which selects data from the optical data input port or the network port.
 4. The active unit according to claim 3, wherein the processor is arranged to monitor the receipt of a periodic enablement signal transmitted from the central control unit, and further arranged to disable the optical data input port when a predetermined number of periodic enablement signals are determined not to have been received.
 5. The active unit according to claim 3, wherein the active unit is arranged to operate in a first mode in which the optical data input port is enabled and the processor is arranged to receive and decode optical data for transmission to the central control unit, and a second mode in which the optical data input port is enabled and the processor is arranged to be interrogated by the central control unit to determine whether optical data is received, prior to decoding the optical data.
 6. The active unit according to claim 3, wherein the multiplexer assigns a higher priority to data received from the optical data input port than from the network port.
 7. The active unit according to claim 3, wherein, the multiplexer selects data from the optical data input port when data is received from the optical data input port and selects data from the network port when data is not received from the optical data input port.
 8. The active unit according to claim 7, further comprising a logic unit which is arranged to control the multiplexer, the logic unit including a first input for receiving the enable signal and a second input for receiving a signal indicating if an optical signal is being received, and wherein the logic unit is arranged to control the multiplexer to select data from the optical data input port when the optical data input port is enabled and the optical signal is received.
 9. The active unit according to claim 1, wherein the active unit is a detector unit.
 10. The active unit according to claim 1, wherein the active unit includes: a smoke detector; a flame detector; a heat detector; or a movement detector.
 11. The active unit according to claim 1, further comprising any one of: an isolator unit; a switch; a sounder; and a warning beacon.
 12. The active unit according to claim 1, wherein the optical data input port is an infra-red port, and the optical data is IR data.
 13. A fire detector system including: an active unit, comprising: a processor; a network port for connection to a central control unit; an optical data input port arranged to receive optical data; an optical signal detector which detects a presence of optical signals received by the optical data input port; and a watchdog unit arranged to monitor the received optical data; wherein the processor is arranged to enable the optical data input port on receipt of an enable signal received by the active unit from the central control unit via the network port; and wherein the watchdog unit is arranged such that, if more than a predetermined amount of data is received which is not recognized as data relating to the active unit, the optical data input port is disabled; a remote communication device including an optical data output port arranged to transmit the optical data to the optical data input port of the active unit.
 14. The fire detector system according to claim 13, wherein the remote communication device further comprises an optical data input port arranged to receive optical data.
 15. The fire detector system according to claim 13, wherein the remote communication device further includes a processor unit arranged to generate data for transmission from the optical data output port of the remote communication device.
 16. The fire detector system according to claim 13, wherein the remote communication device further comprises a display.
 17. The fire detector system according to claim 13, wherein the remote communication device further comprises a user input.
 18. A fire detector system including: an active unit, comprising: a processor; a network port for connection to a central control unit via a fire detector network; an optical data input port arranged to receive optical data; an optical signal detector which detects a presence of optical signals received by the optical data input port; and a watchdog unit arranged to monitor the received optical data; wherein the processor is arranged to enable the optical data input port on receipt of an enable signal received by the active unit from the central control unit via the fire detector network; and wherein the watchdog unit is arranged such that, if more than a predetermined amount of data is received which is not recognized as data relating to the active unit, the optical data input port is disabled; the central control unit having: a network port for communication to the active unit via the fire detector network; and an optical data port enabler arranged to generate the enable signal to the active unit via the fire detector network.
 19. The fire detector system according to claim 18, wherein the central control unit further includes an optical data port disabler arranged to direct a disablement signal to the active unit via the fire detector network.
 20. The fire detector system according to claim 18, wherein the active unit comprises an optical data output port, the active unit being arranged to transmit a periodic handshake signal for establishing communication between the active unit and the remote communication device.
 21. The fire detector system according to claim 18, wherein the active unit further comprises a visual indicator arranged to periodically indicate to a user that the optical data input port is enabled.
 22. A method of communicating with an active unit of a fire detector network, wherein the active unit includes an optical data input port comprising: generating an optical data input port enablement signal at a central control unit which is arranged on the fire detector network; receiving the optical data input port enablement signal in the active unit; and enabling the optical data input port of the active unit including detecting the presence of optical signals with an optical signal detector.
 23. The method according to claim 22, further comprising receiving an optical data input signal via the optical data input port.
 24. The method according to claim 23, further comprising transmitting optical data from an optical data output port of the active unit.
 25. The method according to claim 22, wherein the optical data input port enablement signal is generated periodically at the central control unit, the method further comprising: monitoring the periodic receipt of the optical data input port enablement signal at the active unit, and disabling the optical data input port of the active unit where it is detected that a predetermined number of the optical data input port enablement signals are not received in a period.
 26. A networked fire detector system, comprising: a plurality of detectors, each of the detectors comprising an optical data port including an IR receiver and an IR transmitter; a central control unit for commanding the detectors; a wired network that supplies power to the plurality of detectors and functions as a communication network for transmitting communications between the detectors and the central control unit; and a portable programming tool for communicating with the detectors via the IR receivers and the IR transmitters, wherein during commissioning of the detectors, the portable programming tool transmits initiation signals to the detectors via the IR receivers and the detectors respond by transmitting handshake signals to the portable programming tool via the IR transmitters if the detectors have received enablement signals from the central control unit via the wired network that enables the optical data ports, wherein the detectors transmit configuration data, which was received from the central control unit, to the portable programming tool.
 27. The system according to claim 26, wherein each of the detectors further comprises a watchdog unit that monitors optical data received via the optical data port and disables the optical data port in response to receiving unrecognized data at the optical data port. 